1. Technical Field of the Invention
The present invention relates generally to an improved structure of a pulse-width modulator suitable for integration and a sensing device using the same.
2. Background of Related Art
The present-day automotive vehicles usually use a number of pressure sensors which output analog signals. A control computer into which the outputs of the pressure sensors are inputted thus needs an A/D converter, thereby resulting in an increase in port in the control computer.
As an alternative to the A/D converter, a pulse-width modulator may be employed which converts the output of the sensor into a pulse width-modulated (PWM) signal. The control computer calculates the pulse width of the sensor output using a counter to determine a parameter sensed by the sensor.
In recent years, semiconductor pressure sensors are being decreased in number of component parts for decreasing manufacturing costs and becoming prevalent in compact structure in which sensing elements such as strain gauges and a signal processing circuit are integrated. This, therefore, requires integration of the pulse-width modulator.